The impressive thing about Rifkind
is that he couldn't conceive that his activities could be morally or ethically wrong, even if they're not technically illegal (yet?). THAT is the reason why he has to go. We do not want or need politicians who cannot tell right from wrong - possibly better to have a crook who at least knows and accepts he's a wrong 'un.
Having said that, taking money to arrange 'introductions' to government officials surely must be illegal.